Abstract: A process for preparing N-phosphonomethyl iminodiacetic acid wherein solutions of an alkali metal salt of IDA are reacted with formaldehyde so as to form the alkali metal salt of hydroxymethyliminodiacetic acid (HMIDA). The HMIDA can be subsequently reacted with a phosphorous source such as phosphorous acid to produce PMIDA in good yield.

Abstract: Novel N-acyl derivatives of ethylenediaminetriacetic acid are disclosed, as well as a process for preparing the same.

Abstract: Synthesis of ethylenediaminetriacetic acid (ED3A) or its salts is disclosed. A salt of N,N'-ethylenediaminediacetic acid (ED2AH.sub.2) is condensed with formaldehyde to form a stable 5-membered ring intermediate. The addition of cyanide across this cyclic material forms ethylenediamine N,N'-diacetic acid-N'-cyanomethyl or salts thereof (mononitrile-diacid). The nitrile in aqueous solutions may be spontaneously cyclized to form 2-oxo-1,4-piperazinediacetic acid (3KP) or salts thereof, which is the desired cyclic intermediate. In the presence of excess base, salts of ED3A are formed in excellent yield and purity. Alternatively, the starting material is ED2AH.sub.a X.sub.b, where x is a base cation, e.g., an alkali or alkaline earth metal, a is 1 to 2, and b is 0 to 1 in aqueous solutions. The reaction mixture also can be acidified to ensure complete formation of carboxymethyl-2-oxopiperazine (the lactam) prior to the reaction. Formaldehyde is added, essentially resulting in the hydroxymethyl derivative.

Abstract: A process for producing iminodiacetonitrile (IDAN) from glycolonitrile and ammonia or its salt is disclosed. In the batch process, pH is controlled with the addition of ammonia or suitable acids. In the continuous process, glycolonitrile and ammonia are reacted in near stoichiometric amounts at a temperature from about 90.degree. C. to about 180.degree. C.

Abstract: A process for recovering iminodiacetonitrile (IDAN) values from an aqueous IDAN solution comprising: (a) extracting the aqueous IDAN solution with methylene chloride to dissolve a portion of IDAN in the methylene chloride to form a methylene chloride solution of IDAN; and (b) separating and recovering the IDAN values from the methylene chloride.In an alternative embodiment the IDAN values can be separated from the methylene chloride solution of IDAN by extracting the methylene chloride solution with an aqueous alkali metal hydroxide solution to form water-soluble dialkali metal iminodiacetate (IDAM.sub.2 wherein M is an alkali metal cation) which remains in the aqueous alkali metal hydroxide solution. The IDAM.sub.2 can be recovered from the alkali metal hydroxide solution by conventional methods (e.g., by treating with a strong acid to precipitate iminodiacetic acid (IDA)).

Abstract: Iminodiacetonitrile is prepared in a batch process comprising the addition of HCN to an acidified solution of hexamethylenetetramine while maintaining the resulting solution at a temperature of 20.degree.-90.degree. C. by cooling and at a pH of 5.5-6.5 by the addition of formaldehyde.